1. Field of the Application
The present application relates to the field of communication, and especially to a method, an apparatus and a system for transmitting channel state information.
2. Description of the Related Art
In a Multiple-input Multiple-output (MIMO) system, it is necessary for a base station (BS) to acquire channel state information (CSI) from a mobile station (MS) and to perform communication according to the CSI information by using Space Division Multiple Access technology.
Because of limitation by the number of coded bits, it is difficult for the MS to transmit complete CSI information to the BS. In order to enable the BS to acquire the CSI information, a way of quantizing the complete CSI information is adopted at the MS so as to transmit limited CSI information to the BS. Specifically, in a single-cell MIMO system, a codebook for quantizing the CSI of a channel between the BS and MS is preset, and the MS uses the codebook to quantize the CSI information and then transmit the quantized CSI information to the BS.
During implementation of the embodiments described below, the inventor found that the number of cooperative BSs changes dynamically according to the change of the location of the MS in a cooperative MIMO system, and therefore it is impossible to set a codebook for quantizing the CSI information of the channel between the cooperative BSs and the MS in advance for the cooperative MIMO system. As a result, the MS cannot transmit the CSI information to the cooperative BSs.